1. Field of the Invention
The present invention relates to an oral non-food composition comprising a high viscosity slow-release material.
2. The Related Art
Modern dental hygiene products typically contain ingredients included to provide a benefit to the consumer. Such ingredients include antimicrobial agents, e.g. Triclosan; anti-caries agents, e.g. fluoride and flavours such as peppermint extract to name but a few.
An obvious problem with including agents in oral preparations is that within a short period of time much of the agent is removed from the oral cavity through the action of rinsing or because of the increased salivation in response to something being put into the oral cavity. The fact that the average consumer brushes approximately once every twelve hours only exacerbates the problem of localising enough agent to have an effect.
There is, therefore, a need for an oral composition which is capable of prolonging the effect of such ingredients.
The prior art includes oral compositions comprising an agent which attempts to prolong the action of such actives. For example U.S. Pat. No. 2,806,814 (Richter) discloses an oral composition comprising a silicone compound and a higher aliphatic acyl amide of an amino carboxylic acid compound. The silicone is stated to act synergistically with the acyl amide to improve the latter antimicrobial and acid inhibiting activity.
EP-B1-0 528 457 (Unilever) describes dentifrice compositions comprising a non-cyclic, hydrophobic amino alkyl silicone in an oil in water emulsion. The silicone is said to form a layer on the teeth and dissolve the antibacterial active. Thus, the active is maintained at the desired location.
EP-B1-0 518 924 (Rolla) discloses a dentifrice composition comprising a silicone oil and a fat-soluble antimicrobial other than hexyl resorcinol. The silicone oil is preferably a diphenyl or di(C1-C4) alkyl-polysiloxane which the antimicrobial agent is preferably an antiseptic phenol such as Triclosan (2xe2x80x2,4,4xe2x80x2-trichloro,2-hydroxy-diphenyl ether). The silicone is preferably a liquid silicone such as those disclosed in U.S. Pat. No. 2,806,814.
None of the above disclosures describes an oral non-food composition comprising a high viscosity slow-release material such as is required in the invention.
Further examples of disclosures describing the use of silicones in dentifrice compositions include GB 689 679 which discloses a mouthwash comprising an organopolysiloxane. The silicone is included in order to coat the teeth and, thereby, prevent adhesion of food particles, tartar etc. and so reduce staining.
WO 94/14405 (Rydxc3xa9n) discloses dentifrice compositions comprising a dimethyl polysiloxane with a viscosity in the range of 0.4 to 100xc3x9710xe2x88x923 m2sxe2x88x921 at 25xc2x0 C. However, the preferred silicones have a viscosity of 0.2 to 5xc3x9710xe2x88x923 m2sxe2x88x921 and the exemplified material, SF-96 (ex. General Electric) has a viscosity towards the bottom end of this preferred range.
Additionally the toothpaste according to this invention requires at least 5% siloxane to achieve the improvement in abrasion.
U.S. Pat. No. 3,507,955 (Osipow) discloses oral compositions comprising 3 to 7% by weight of an anti-caries agent which is a dimethyl siloxane having a viscosity of 0.05 to 5xc3x9710xe2x88x923 m2sxe2x88x921, preferably 0.2 to 1xc3x9710xe2x88x923 m2sxe2x88x921.
WO 95/15740 (3M) discloses a coating for teeth to reduce or prevent adhesion of bacteria and proteinaceous material. These coatings comprise a hydrophobic graft polysiloxane chain having a molecular weight of at least 500.
EP-B1-0 373 688 (Unilever) discloses dentifrices comprises an amino alkyl silicone. While silicones with a molecular weight of 10000 to 30000 are preferred, however, providing that the silicone spreads over the teeth enamel by brushing and rinsing there is no maximum or minimum molecular weight.
EP-B1-0 371 551 (Unilever) discloses a dentifrice composition comprising an amino alkyl silicone which has a molecular weight between 5000 and 100000 it is also noted that a viscosity in the range of 0.05 to 3xc3x9710xe2x88x923 m2sxe2x88x921 (page 5, line 9) is required.
EP-B1-0 528 457 (Unilever) discloses dentifrice compositions comprising an amino alkyl siloxane. The siloxane preferably has a molecular weight ranging from 5000 to 100000 which those silicones with a molecular weight as high as 1000000 or more may also be used. However, the preferred viscosity for the amino alkyl siloxane ranges from 0.05 to 3xc3x9710xe2x88x923 m2sxe2x88x921 (page 5, line 51).
GB 1 194 885 (Pre-Coat Corp) discloses dentifrices comprising silicone oils which will preferentially coat teeth. The dimethyl polysiloxanes usually have a viscosity of 0.04 to 100xc3x9710xe2x88x923 m2sxe2x88x921 at 25xc2x0 C. and the preferred siloxanes have a viscosity in the range 0.2 to 5xc3x9710xe2x88x923 m2sxe2x88x921. The exemplified silicone SF-96 has a viscosity ranging from 0.5 to 10xc3x9710xe2x88x923 m2sxe2x88x921.
Thus, it is a primary object of the invention to provide an oral, non-food composition which comprises a high viscosity, slow-release material which prolongs the effect of therapeutic, sensory or other active agents contained therein.
Accordingly, the invention provides an oral, non-food composition which includes an active agent that is substantially insoluble in water at room temperature and pressure and a silicone with a viscosity within the range 10xc3x9710xe2x88x923 to 90xc3x9710xe2x88x923 m2sxe2x88x921 at 25xc2x0 C., characterised in that the composition comprises an intimate blend of the active and silicone.
An essential feature of the invention is the silicone which effects a slow release of beneficial active agents additionally present in the composition. Such a silicone is thus capable of prolonging the effect of such beneficial active agents in the oral cavity. In order to provide such an intimate blend of active and silicone it is preferred that the two are admixed before blending with the remaining ingredients of the composition.
Silicones according to the present invention may include any of the organopolysiloxanes known in the art which have a viscosity ranging from 10xc3x9710xe2x88x923 to 90xc3x9710xe2x88x923 m2sxe2x88x921. Examples of such silicones include dimethyl siloxanes, e.g. the 200 series available commercially from Dow Corning.
Preferably, the slow-release material of the invention is a silicone having a viscosity ranging from 10xc3x9710xe2x88x923 to 90xc3x9710xe2x88x923 m2sxe2x88x921, more preferably from 30xc3x9710xe2x88x923 to 90xc3x9710xe2x88x923 m2sxe2x88x921 and especially between 50xc3x9710xe2x88x923 and 70xc3x9710xe2x88x923 m2sxe2x88x921.
An object of the invention is the prolonging of an effect of an active agent. Such an active agent may have any of a number of effects, e.g. therapeutic, sensory or cosmetic. It may even have a combination of any of these or other effects.
In a preferred embodiment of the invention the active agent is one which is substantially insoluble in water. By substantially insoluble means that the agent may be sparingly soluble. Such agents include tin pyrophosphate, zinc citrate, magnesium fluoride and calcium fluoride to name a few. Such actives are typically present at amounts ranging from 0.01 to 10% by weight, preferably from 0.5 to 5% by weight.
The silicone of the present invention is particularly suitable in so-called xe2x80x98double-pump productsxe2x80x99 where two formulations are stored in separate containers and mixed immediately prior to use. Typical of such double-pump products is that marketed by Unilever under the brand name Mentadent(copyright) in the US where a gel formulation comprising hydrogen peroxide and a paste formulation comprising sodium bicarbonate are stored separately and mixed immediately prior to use to allow the creation of oxygen bubbles in the oral cavity.
A problem with using silicones in dentifrice formulations is that the silicone acts as an anti-foam agent and the anti-foam effect is proportional to the length of chains in the silicone: the longer the silicone chain the greater the effect. For this reason long-chain silicones have not been readily used as ingredients in dentifrice formulations.
However, we have surprisingly found that a silicone according to the invention can be successfully incorporated into the peroxide gel formulation of a double-pump product, additionally comprising a bicarbonate paste formulation, and not significantly reduce the foaming of the dentifrice when the two formulations are combined.
A composition according to the invention will comprise from 0.001 to 10% by weight of the silicone, preferably from 0.1 to 3% and especially from 0.2 to 2%.
The composition according to the invention may be any oral, non-food composition, e.g. toothpaste and may be in the form of a gel, paste, gum or any other suitable type.
In a further aspect to the invention there is provided the use of a silicone having a viscosity ranging from 10xc3x9710xe2x88x923 to 90xc3x9710xe2x88x923 m2sxe2x88x921 at 25xc2x0 C. in an oral composition as a slow-release material for an active agent.
All viscosities in this application are at 25xc2x0 C. unless otherwise stated and can be measured on a Brookfield Viscometer according to standard protocols.
The composition according to the invention may also comprise ingredients which are common in dentifrices. Examples of such ingredients include:
antimicrobial agents, e.g. Triclosan, chlorhexidine, copper-, zinc- and stannous salts such as zinc citrate, zinc sulphate, zinc glycinate, sanguinarine extract, metronidazole, quaternary ammonium compounds, such as cetylpyridinium chloride; bis-guanides, such as chlorhexidine digluconate, hexetidine, octenidine, alexidine; and halogenated bisphenolic compounds, such as 2,2xe2x80x2 methylenebis-(4-chloro-6-bromophenol);
anti-inflammatory agents such as ibuprofen, flurbiprofen, aspirin, indomethacin etc.;
anti-caries agents such as sodium or stannous fluoride, aminefluorides, disodium monofluorophosphate, sodium trimeta phosphate and casein;
plaque buffers such as urea, calcium lactate, calcium glycerophosphate and strontium polyacrylates;
vitamins such as Vitamin C;
plant extracts;
desensitising agents, e.g. potassium citrate, potassium chloride, potassium tartrate, potassium bicarbonate, potassium oxalate, potassium nitrate and strontium salts;
anti-calculus agents, e.g. alkali-metal pyrophosphates, hypophosphite-containing polymers, organic phosphonates and phosphocitrates etc.;
gum protection agents, e.g. vegetable oils such as sunflower oil, rape seed oil, soybean oil and safflower oil; silicone oil; and hydrocarbon oil. The gum protection agent may be an agent capable of improving the permeability barrier of the gums. A complete description of agents capable of improving the permeability barrier of the gum is found in our co-pending application GB;
biomolecules, e.g. bacteriocins, antibodies, enzymes, etc.;
flavours, e.g. peppermint and spearmint oils;
preservatives;
opacifying agents;
colouring agents;
pH-adjusting agents;
sweetening agents;
pharmaceutically acceptable carriers, e.g. starch, sucrose, water or water/alcohol systems etc.;
surfactants, such as anionic, nonionic, cationic and zwitterionic or amphoteric surfactants;
particulate abrasive materials such as silicas, aluminas, calcium carbonates, dicalciumphosphates, calcium pyrophosphates, hydroxyapatites, trimetaphosphates, insoluble hexametaphosphates and so on, including agglomerated particulate abrasive materials;
humectants such as glycerol, sorbitol, propyleneglycol, xylitol, lactitol etc.;
binders and thickeners such as sodium carboxymethyl-cellulose, xanthan gum, gum arabic etc. as well as synthetic polymers such as polyacrylates and carboxyvinyl polymers such as Carbopol(copyright);
buffers and salts; and
other optional ingredients that may be included are e.g. bleaching agents such as peroxy compounds e.g. potassium peroxydiphosphate, effervescing systems such as sodium bicarbonate/citric acid systems, colour change systems, and so on.